The invention relates to encoding methods for use by a digital transmission system in generating for transmission via a transmission medium, a digital signal representing a wide-band digital signal, for example, a digital audio signal sampled with a specific sample frequency F.sub.S. Such a system includes a transmitter having an input terminal for receiving the wide-band digital signal, which input terminal is coupled to an input of a first encoder. The first encoder includes a subband coder responsive to the wide-band digital signal to generate a plurality of M subband signals with sample frequency reduction, for which purpose the subband coder divides the wide-band digital signal into successive subbands having band numbers m which increase as the frequency increases, where 1.ltoreq.m.ltoreq.M; a quantization unit for the blockwise quantization of the respective subband signals to produce quantized samples in the signal blocks, a subband signal being composed of consecutive signal blocks, each signal block comprising q samples; and a bit allocation unit for generating bit allocation information specifying the number of bits representative of each of the q samples in a signal block. The transmitter further comprises a scale-factor information determiner for determining information related to a scale factor belonging to each signal block of a subband signal; a combining unit for combining the quantized samples in the signal blocks, the scale factor information and the bit allocation information in a frame of a second digital signal formed by successive frames; a second encoder for converting the second digital signal into a third digital signal so as to enable the third digital signal to be transmitted via the transmission medium; and an application unit for applying the third digital signal to the transmission medium.
The invention also relates to record carriers containing the signal produced by the transmission system.
A transmission system of the type defined in the opening paragraph is known from European Patent Application No. 04.02.973, which corresponds to U.S. patent application Ser. No. 07/997,158, filed Dec. 21, 1992, and is incorporated herein by reference. The known system is a recording and reproducing system of the DCC type, in which a digital audio signal is recorded in one or more tracks on a magnetic record carrier. Another possible field of use of the invention is digital transmission, such as digital audio broadcasting (DAB).